The plant at 2865 Riverport Road took 18 months to build with the groundbreaking during the historic flooding along the Mississippi River in 2011.

The $200 million investment by Mitsubishi includes a 13-story testing hall at the end of the assembly line that comes with a 500-ton crane to lift the mammoth transformers onto rail cars on a line that runs directly into the structure.

The transformers and electrical equipment are so massive that they are too large for Memphis Light, Gas and Water Division to use for its needs, according to Ken Badaracco, Mitsubishi Memphis general manager.

The building on 97 acres has 307,000 square feet of manufacturing space and another 52,000 square feet of office space.

The $200 million Mitsubishi Electric Power Products Inc. plant is the company’s first North American plant for large power transformers, some weighing in excess of 400 tons.

As of Friday’s opening, 65 people are working full time at the plant. Mitsubishi executives intend to have 275 employees when the plant is at full capacity.

The other big economic prize, the Electrolux Memphis manufacturing plant, is expected to begin turning out ovens and ranges in May.

The $266 million plant in Frank C. Pidgeon Industrial Park, near the Mitsubishi facility, is expected to employ 1,200 people making several product lines of stoves and ovens.

Electrolux executives offered a tour of the plant in January just as the $60 million assembly line by Memphis-based Integrated Solutions was beginning to take shape.

The Electrolux plant opening is expected to be a phased-in operation that adds product lines over time.